| Abbreviation | Definition |
|---|---|
| EI | Engineering Instruction |
| EI | Entry Interface |
| EI | Environmental Impact |
| EIASN | End Item Assembly Sequence Number |
| EIC | Experimental InterCom |
| EICAS | Engine Indication and Crew Alerting System |
| EID | End Item Documentation |
| EID | Experiment Interface Document |
| EIDP | End Item Data Package |
| EIFA | Element Interface Functional Analysis |
| EIRP | Effective Isotropic Radiated Power |
| EIS | Electrical Integration System |
| EIS | End Item Specification |
| EIS | Extended Instruction Set |
| EIT | Entry Interface Time |
| EIT | Extreme-ultraviolet Imaging Telescope |
| EIU | Engine Interface Unit |
| EIV | Emergency Isolation Valve |
| EIVC | Early Inlet Valve Closing |
| EIVT | Electrical and Instrumentation Verification Test |